DESCRIPTION: (Applicant's Description) Specific Aim 1. To provide packaged viral vectors for laboratory research in the Stem Cell Biology and Transplant Program. Retrovirus vectors and lentivirus vectors will be constructed either in the laboratory of the investigator or in the Vector Core Laboratory. The Vector Core will then use the vector construct DNA in transfections to generate viral vector, also conducting necessary quality control analyses (titer, helper assays), thus providing the final vector product to the investigator for experiments described in each individual section of this Program Project Grant proposal. Specific Aim 2. To provide clinical-grade retro viral vectors for human trials conducted as a part of the Stem Cell Biology and Transplant Program. Clinical-grade retro viral vector will be produced under cGMP conditions at the Molecular and Cellular Therapeutics Facility, St. Paul Campus of the University of Minnesota, for use in human clinical trials to be carried out as a part of the Stem Cell Biology Research Program. Clinical-grade vectors planned for production include marking vector for human hematopoietic and mesodermal progenitor cells (Projects 2, 3 and 5), vectors transducing drug resistance genes (Project 3), and vectors transducing the human alpha-Liduronidase gene (Project 5).